47P/Ashbrook-Jackson (0047P)
Type: Periodic
Perihelion date: 27 October 2025
Perihelion distance (q): 2.8
Aphelion distance (Q) : 5.4
Period (years): 8.4
Eccentricity (e): 0.32
Inclination (i): 13.0
JPL orbit diagram
COBS lightcurve
Atlas
This comet was independently discovered by astronomers in the United States and
South Africa. The first discovery was made by Yale astronomer Joseph Ashbrook.
Ashbrook was visiting Lowell Observatory (Arizona, USA) to observe minor planets.
While examining a photo exposed on 26 August 1948 for asteroid 1327 Namaqua, he
found the comet and said it appeared diffuse, with a short tail.
Twelve hours later, Cyril Jackson (Yale-Columbia Station, Johannesburg, South
Africa) was experimenting with a 50-cm focus camera to test its ability to photograph
fast moving minor planets. This comet was revealed on one of the plates.
The comet has been observed at every return following the 1948 discovery. Despite
the large perihelion distance it typically reaches a magnitude brighter than 12 as it is
one of the intrinsically brightest short-period comets.
Observations (VEMag = visual equivalent magnitude)
Date
10x10 mag
Error
VEmag
Coma '
20-Jul-17
17.53
0.03
16.4
0.3
30-Jul-17
17.52
0.04
16.5
0.3
25-Aug-17
17.15
0.03
16.4
0.3
28-Aug-17
17.19
0.03
16.0
0.4
16-Sep-17
16.99
0.01
16.0
0.6
27-Sep-17
16.89
0.04
15.8
0.6
23-Nov-17
17.39
0.02
16.3
0.3
04-Jan-18
18.25
0.04
17.1
0.3
14-Feb-18
18.77
0.05
18.4
0.2